RHIZOPODA. 
Prot. 9 
nucleus changes its place, migrating through the narrow sarcodal passage 
connecting the chambers. Schulze further makes use of this discovery 
for a discussion of the limits and natural (phylogenetic) arrangement 
of the Rhizopoda, uniting with them the Monera and Protoplasta, but 
keeping apart the Labyrinthulece, Myxomycetes, and Flagellata. Con- 
sidering the non-nucleated types as the lower and older, he derives from 
Protamceha and similar lobose forms, the nucleate Amceha, Pelomyxa, 
Ilyalosphenia, Quadrula^ Arcella^ and Difflugia ; also, several forms 
with mere abnormal shapes of the pseudopodia : CocJiliopodium, Placopus^ 
Podostoma, Petalopus. M^jxastrum, Vampyrella, and Protogenes may, in 
the same manner, be considered the more primitive non-nucleated repre- 
sentatives of the Nucleata radiosa : Nuclearia (= Leptophrys, Hetero- 
phrys, Heliophrys'), Pedunculata {ClathruUna, Lecythia, &c.), Heliozoa 
{Acanthocystis, Acanthosphoirium)^ and of the more highly organized 
Radiolaria, distinguished by the presence of a “ central capsule ” ; while 
Protomxya (and Myxodictyum) are the innucleate prototypes of the 
N. reticularia, comprising naked forms such as Lieberkuhnia and the 
host of imperforate and perforate shelled Thalamophora (Hertw.) ; the 
Diplostomida, Gromia, Euglypha, Miliola, and Litvola being the chief 
types of the imperforate, Lagena, Globigerina^ and Nummulites of the 
perforate division. 
Hertwig (11) further arrives at the following results concerning the 
structure and propagation of thepolyzoan Radiolarian, Collozomn inevme. 
The zooids of the colony are connected through the network of the anas- 
tomosing pseudopodia and an imbedding gelatine ; they consist of the 
“central capsule” and the extra-capsular sarcode with its nucleated 
“ yellow cells ” and vacuoles (alveoli) ; probably the extra- and intra- 
capsular sarcode are in communication through minute pores in the mem- 
brane of the capsule, which is equivalent to a multi-nucleate cell 
(or syncytium), and contains one or several “oil-globules”; these 
are, however, not simply drops of fat, but contain an albuminous sub- 
stratum. The nuclei of the central cell multiply by division, as does 
the cell (central capsule) itself, forming in this manner new zooids 
in the colony, or, by subdivision of the colony, new colonies or aggre- 
gates of individuals. True propagation is performed by the evolu- 
tion and liberation of the numerous minute uniflagellate and nucleate 
zoospores, into which the whole contents of the “central capsule” 
is transformed, the extra-capsular elements disappearing during the 
process. In some colonies, each zoospore is provided with a crystal- or 
rod-like corpuscle ; in others (perhaps specifically distinct), the zoospores 
have a somewhat different shape, are devoid of this corpuscle, and 
differentiated into “ macrospores ” and “ microspores.” The same propa- 
gation by “zoospores,” produced chiefly by a metamorphosis and disin- 
tegration of the contents of the “ central-globule, is demonstrated in 
the (monozoic) Thalassicolla^ and is therefore probably characteristic of 
all Radiolaria. Hertwig is inclined to form a special division (Collida) 
of the genera, which, like Thalassicolla, Tlialassolampe, Myxobrachia, 
Physematium^ Aulacantha, Aulosphcera^ Heliosphcera^ Diplosphcera^ have 
primordially a highly differentiated nucleus (the “internal vesicle”), pro- 
